Device and process for feeding sheets to a finishing line for documents formed from these sheets

ABSTRACT

The device ( 1 ) for feeding sheets to a finishing line for documents formed from these sheets comprises, for supporting a pack ( 4 ) of sheets, a table ( 5 ) which cooperates with sheet extraction means ( 6 ) for transferring a sheet, to a filter ( 8 ) defining a slot ( 9 ), and to means ( 11 ) for its expulsion towards the finishing line. The device comprises means ( 13 ) for adjusting the thickness of the slot ( 9 ) and/or means ( 15 ) for controlling the force exerted by the extraction means ( 6 ). The process for feeding sheets to a finishing line comprises the steps of extracting a sheet from a pack ( 4 ), passing the sheet ( 7 ) through a slot ( 9 ) which allows one sheet at a time to pass, and expelling the sheet ( 7 ) towards the finishing line. The thickness of the slot ( 9 ) and/or the extraction force exerted on each sheet extracted from the pack ( 4 ) are automatically adjusted.

The present invention relates to a device and process for feeding sheets to a finishing line for documents formed from these sheets.

Specific reference will be made hereinafter to a device and process for feeding sheets to a finishing line in which the individual sheets are collected together to form a finished document which can comprise, for example, a cover, a text, and attachments.

The cover, the text and the attachments are usually formed from paper of different characteristics, for example the cover is formed from paper of large thickness and high rigidity, the text from paper of lesser thickness and the attachments of special paper of photographic or other type.

In practice, in forming an individual document, sheets of extremely different characteristics have to be joined together.

Sheets for document formation are currently made available in orderly piles, from which the sheets have to be extracted and fed to the finishing line where they are joined together to form the final document.

For this purpose the pile is supported by a sheet dispenser connected to the feeder device.

The sheet dispenser supports the pile of sheets to be handled in forming the document, and supplies the sheets to the feeder device.

The feeder device in its turn supports the feed sheets as a pack of predefined small dimensions (usually about one centimetre thick) which is continuously fed (by the sheet dispenser) to maintain its thickness substantially constant; a photosensor senses the extraction of a sheet from the feeder pack and causes the sheet dispenser to provide new sheets to maintain the thickness constant.

In traditional devices the means for extracting sheets from the pack are in the form of rubber coated rollers which compel the sheets to pass through a slot sized to enable one sheet at a time to pass; expulsion rollers then feed the sheets to the finishing line.

In other arrangements, the extraction means comprise a perforated rotating roller connected to a vacuum pump; the roller faces a surface on which the pack of sheets rests, and is able to adhere to a sheet by virtue of the vacuum generated by the pump; the sheet adhering to the rotating roller is fed through the slot and then expelled towards the finishing line.

The slot is adjusted manually, to enable one sheet at a time to pass, each time the type of paper used is changed; this adjustment is made by a screw.

Traditional feeder devices present numerous drawbacks, mainly due to the fact that they require the presence of an operator to make the necessary adjustments each time the device handles a type of paper with characteristics different from the preceding.

This results in continuous interruptions in machine operation to make the new manual adjustments, with a consequent fall in production and high document production costs.

The technical aim of the present invention is therefore to provide a device and process for feeding sheets to a finishing line for documents formed from these sheets by which the stated technical drawbacks of the known art are eliminated.

Within the scope of this technical aim, an object of the invention is to provide a device and process which are automatic and do not require the presence of an operator to make adjustments when the characteristics of the paper handled by the device change; in particular, the thickness, the porosity and/or the rigidity of the paper can change.

Another object of the invention is to provide a device and process which enable high productivity to be achieved with low production costs.

The technical aim together with these and other objects, are attained according to the invention by a device and process for feeding sheets to a finishing line for documents formed from these sheets, in accordance with the accompanying claims.

Further characteristics and advantages of the invention will be more apparent from the description of a preferred but non-exclusive embodiment of the device and process, the device being illustrated by way of non-limiting example in the accompanying drawings, in which:

FIG. 1 is a schematic view of the device of the invention; and

FIG. 2 is a perspective view of an upper portion of the device.

Said figures show a device for feeding sheets to a finishing line for documents formed from these sheets, in which the device is indicated overall by the reference numeral 1.

The device 1 is shown associated with a sheet dispenser 2 which carries a pile of sheets 3 fed in known manner to the device 1 as indicated by the arrow A, such that a sheet pack 4 of substantially constant thickness (equal to about one centimetre) is formed and maintained.

The device 1 comprises, for supporting the sheet pack 4, a table 5 which cooperates with means 6 for extracting the sheets; these extraction means are arranged to transfer a sheet 7 extracted from the pack 4 to a filter 8 defining a slot 9.

The slot 9 is arranged to allow one sheet 7 at a time to pass (while preventing the passage of two or more superposed sheets).

In series with the filter 8, the device 1 presents means 11 for expelling the sheets towards the finishing line (not shown); these expulsion means consist of rollers coated with rubber or another material of high friction coefficient.

Advantageously, the device 1 comprises means 13 for adjusting the thickness of the slot 9 and/or means 15 for controlling the extraction force exerted by the extraction means 6, in order to be able to extract from the pack 4, and supply to the finishing line, sheets for one and the same document which present different thickness and/or porosity.

As shown in the accompanying figures, the extraction means 6 comprise a movable portion 16 provided with at least one aperture 17 and associable by vacuum with the sheet 7 to be extracted; in practice, when the movable portion 16 is associated with a sheet 7, it can drag the sheet 7 towards the filter 8.

The movable portion 16 is supported by the support table 5 and is in the form of a hollow cylinder (indicated by 16) provided with apertures (indicated by 17) arranged in several parallel rows and connecting its interior chamber 18 to the outside.

Within the chamber 18 a hollow element 19 is slidable and presents a row of holes 20 alignable alternately with a row of apertures 17; the element 19 also presents an internal cavity 21 connected to a vacuum pump 22.

The vacuum pump 22 creates the vacuum which causes temporary adhesion of the sheet 7 to the cylinder 16; by rotating continuously (possibly with successive controlled starts and stops) as indicated by the arrow F, the cylinder 16 drags the sheet 7 forwards.

Advantageously, the slot 9 is defined between the filter 8 and the cylinder 16 of the extraction means 6.

In this case the means 13 for adjusting the thickness of the slot 9 comprise two members 25 for controlling the position of the support table 5 carrying the extraction means 6; these control members 25 cause a region of the table 5 to approach or withdraw from the filter 8 in order to move the extraction means 6 towards or away from the filter 8 and hence vary the thickness of the slot 9.

The control members 25 comprise two cams which support a first end of the table 5 in correspondence with its opposing lateral edges; the cams are rigid with a wheel driven by a motor 28 (or by two motors).

The table 5 also presents a second end, opposite the first end, which is rigid with two blocks 24 hinged at 26 to a frame 27 of the device 1.

In a different embodiment, the means 13 for adjusting the thickness of the slot 9 comprise an actuator 29 for example of pneumatic or hydraulic type or in the form of an electric motor, to cause a blade 30 of the filter 8 to approach and withdraw from the table 5 on which the sheets rest.

In a further embodiment the device can be provided with both the adjustment means consisting of the cams which move the table 5 and of the actuator which moves the blade 30 of the filter 8.

The means 15 for controlling the extraction force exerted by the extraction means 6 comprise a solenoid valve for throttling the suction flow of the pump 22.

Advantageously, the device also comprises a sensor 33 for reading a code defining information relative to the characteristics of the entering sheets; this information relates to the sheet thickness, porosity, rigidity etc. and is impressed on the sheets.

The sensor 33 is connected to a control processor 34 connected to the means 13 for adjusting the dimension of the slot 9 and/or the means 15 for controlling the extraction force exerted by the extraction means 6; in this manner these parameters can be automatically controlled in relation to the characteristics of the sheet being handled.

The operation of the device of the invention is apparent from that described and illustrated and is substantially as follows.

The sheet dispenser 2 passes the sheets in known manner from the pile 3 to the pack 4 on the table 5; this operation is controlled in known manner by a photosensor (not shown) which, by counting the number of sheets extracted from the pack 4, enables the thickness of the pack 4 to be maintained constant. For example this pack 4 can present a thickness substantially close to 1 centimetre.

The sheets are dragged from the pack 4 one at a time starting from the lower sheet 7, and are passed through the slot 9.

The element 19 is fixed and the chamber 21 is always connected to the vacuum pump 22; in this manner when a sheet is to be removed, the cylinder 16 is rotated (so making the inner surface of the cylinder 16 and the outer surface of the element 19 slide on each other) so that the vacuum in the chamber 21 is able to cause the sheet to be dragged to adhere to the cylinder 16 via the aligned holes 20 and 17.

The sheet 7 is then forced by the cylinder 16 to pass through the slot 9, so detaching any sheets which may adhere to the sheet being dragged.

When the sheets have passed through the slot 9 they are gripped by the rubber coated rollers 11 and are dragged towards the finishing line. Advantageously, the sheets carry an impressed code indicative of their thickness and/or porosity and/or rigidity.

This code is read by the sensor 33 and is transmitted to the processor 34 which regulates the thickness of the slot 9 by rotating the cam 25; this raises or lowers that portion of the table 5 in correspondence with the filter 8.

The movement of the table 5, which carries the cylinder 16, results in increase or decrease of the thickness of the slot 9. Alternatively or simultaneously, the processor 34 operates the actuator 29 which moves the filter blade 30 towards or away from the cylinder 16.

At the same time (or alternatively) the processor 34 regulates the force exerted by the extraction means 6, i.e. the vacuum in the chamber 21; this is achieved by regulating the opening of the solenoid valve 15.

The present invention also relates to a process for feeding sheets to a finishing line for documents formed from these sheets.

The process comprises the steps of extracting from a pack 4 a sheet 7 to be fed to the finishing line to form a document, passing the sheet 7 through a slot 9 which allows one sheet at a time to pass, and expelling the sheet towards the finishing line.

Advantageously, the thickness of the slot 9 and/or the extraction force exerted on each sheet 7 extracted from the pack 4 are automatically adjusted, to extract and feed to the finishing line a single sheet presenting characteristics different from those of a previous sheet.

The process suitably comprises a step by which information, impressed on the sheets, relative to the characteristics of the sheets to be handled is read and processed to adjust the slot dimensions and/or adjust the extraction force exerted by the extraction means.

It has been found in practice that the device and process of the invention for feeding sheets to a finishing line for documents formed from these sheets are particularly advantageous because they enable the process of feeding a finishing line to be automated, so considerably increasing productivity and substantially reducing its associated costs.

The device and process for feeding sheets to a finishing line conceived in this manner are susceptible to numerous modifications and variants, all entering within the scope of the inventive concept; moreover all details can be replaced by technically equivalent elements, In practice the materials used and the dimensions can be chosen at will according to requirements and to the state of the art. 

1. A device (1) for feeding sheets to a finishing line for documents formed from these sheets, comprising, for supporting a pack (4) of sheets, a table (5) which cooperates with sheet extraction means (6) arranged to transfer a sheet (7) extracted from said pack (4) to a filter (8) defining a slot (9) enabling one sheet at a time to pass and to means (11) for expelling the sheets towards the finishing line, characterised by comprising means (13) for adjusting the thickness of said slot (9) and/or means (15) for controlling the force exerted by said extraction means (6), such as to be able to extract from the pack (4), and supply to the finishing line, sheets for one and the same document which are of different thickness and/or porosity.
 2. A device (1) as claimed in claim 1, characterised in that said extraction means (6) comprise a movable portion (16) provided with at least one aperture (17) and associable by vacuum with a sheet to be extracted such that, when said movable portion (16) is associated with a sheet, it can drag the sheet towards said filter (8).
 3. A device (1) as claimed in claim 1, characterised in that at least said movable portion (16) is supported by said support table (5).
 4. A device (1) as claimed in claim 1, characterised in that said movable portion (16) comprises a hollow cylinder provided with a plurality of said apertures (17) connecting its interior chamber (18) to the outside, within said chamber (18) there sliding a hollow element (19) presenting at least one hole (20) alignable with at least some of said apertures (17) of said cylinder, and an internal cavity (21) connected to a vacuum pump (22).
 5. A device (1) as claimed in claim 1, characterised in that said slot (9) is defined between said filter (8) and said extraction means (6).
 6. A device (1) as claimed in claim 1, characterised in that said means (13) for adjusting the thickness of the slot (9) comprise at least one member (25) for controlling the position of said support table (5) carrying said extraction means (6), said control members (25) causing at least one region of said table (5) to approach or withdraw from said filter (8) in order to move said extraction means (6) towards or away from said filter (8) and vary the thickness of said slot (9).
 7. A device (1) as claimed in claim 1, characterised in that said control member (25) comprises at least one cam supporting a first end of said support table (5).
 8. A device (1) as claimed in claim 1, characterised in that said support table (5) presents, opposite said first end, a second end hinged to a frame (27) of said device (1).
 9. A device (1) as claimed in claim 1, characterised in that said adjustment means (13) comprise an actuator (29) arranged to move at least one portion of said filter (8) towards and away from said sheet support table (5).
 10. A device (1) as claimed in claim 1, characterised in that said means (15) for controlling the force exerted by said extraction means (6) comprise a solenoid valve for throttling the suction flow of the pump (22).
 11. A device (1) as claimed in claim 1, characterised by comprising at least one sensor (33) for reading a code which defines information relative to the characteristics of the entering sheets and is impressed thereon, said sensor (33) being connected to a control processor (34) connected to said means (13) for adjusting the dimension of said slot (9) and/or said means (15) for controlling the extraction force exerted by said extraction means (6), to automatically control said parameters in relation to the characteristics of the sheet being handled.
 12. A process for feeding sheets to a finishing line for documents formed from these sheets, comprising the steps of extracting from a pack (4) a sheet (7) to be fed to the finishing line to form a document, passing said sheet (7) through a slot (9) which allows one sheet at a time to pass, and expelling said sheet towards the finishing line, characterised by automatically adjusting the thickness of the slot (9) and/or the extraction force exerted on each sheet extracted from the pack (4), to feed to the finishing line a single sheet presenting characteristics different from those of a previous sheet.
 13. A process as claimed in claim 12, characterised by comprising a step in which a code impressed on the sheets and defining information relative to the sheet characteristics is read, said information being processed to adjust the dimensions of the slot (9) and/or to adjust the extraction force exerted by the extraction means (6). 